It is customary procedure to employ a plurality of shaped charges in perforating subsurface formations, such as, for example, in well bore completion operations. Typically, each charge is made up of a casing which contains explosive material of predetermined configuration and is recessed to receive a conical liner within the casing. When the explosive material is detonated, the liner is propelled with a high degree of force through the carrier wall, outer casing string and cement into the subsurface formation so as to open up the formation for flow of fluid upwardly through the casing string. In the past, the approach has been generally to fabricate the carrier assembly for the explosive material of a reusable material so that following detonation, the carrier can be retrieved. This has presented certain problems in that the construction of the carrier assembly must be such that it is capable of withstanding the explosive force of one or more charges which necessarily are directed through the wall of the carrier; also, expendable portions of the carrier through which the liner of a charge passes often tend to partially disengage from the carrier upon detonation and interfere with the retrieval of the carrier from the casing string.
In copending application for patent, Ser. No. 23,657, filed Mar. 26, 1979 entitled METHOD AND APPARATUS FOR WELL PERFORATION AND FRACTURING OPERATIONS, the foregoing and other problems are alluded to in the construction of a novel shaped charge device intended for perforating and stimulating wells. However, said application has to do more with the definite penetration of the charge into the formation surrounding the well bore as well as the construction and arrangement of various assemblies for use with the various explosive charges as disclosed therein. However, the present invention is concerned more with the construction of the carrier assembly for conventional shaped charges and specifically a way of permitting use of higher capacity charges for given size carriers while avoiding the problem of objectionable interference with the efficient retrieval of the carrier from the casing string.